Research using longitudinal data from the developed world has demonstrated the value of panel surveys for understanding an array of fundamental questions in social science. The Indonesia Family Life Survey of Aging (IFLS) is one such survey, and it has been valuable resource for researchers interested in low income settings. To date we have collected four full rounds of data, in 1993, 1997, 2000 and 2007. All are in the public domain, and in combination have proved highly useful with regard to enhancing our understanding of important economic, demographic, and health behaviors and outcomes related to aging in a low-income setting. We propose to conduct a fifth full round of IFLS in 2013/14. The value added of a fifth round is substantial. IFLS5 will extend the time frame the study spans to 20 years. The proposed data will greatly facilitate the study of demographic, health and socioeconomic change pertaining to the elderly over the life-course, across generations and over a period of time that includes long-run economic growth, sharp economic downturn and recovery. Being able to assess the impacts of a major economic downturn over a longer period of time (15 years subsequent to the shock) makes IFLS unusual among panel surveys. Having panel data over a 20 year period will allow study of how aging processes work over time for the same individual. It will allow a more thorough understanding of a major health transition that is now underway in Indonesia; in which the roles of chronic diseases, overnutrition and associated health risk factors among prime-aged adults and the elderly have increased in importance; at the same time that problems of infectious disease and undernutrition are still quite prevalent. PUBLIC HEALTH RELEVANCE: Twenty Years On: The Fifth Indonesia Family Life Survey of Aging will substantially enrich the international landscape of aging studies. IFLS5 will extend the time frame the study spans to 20 years. The proposed data will greatly facilitate the study of demographic, health and socioeconomic change pertaining to the elderly over the life-course, across generations and over a period of time that includes long-run economic growth, sharp economic downturn and recovery.